Nairobi was once known as a "place of cool waters", derived from the Maasai word enairobe, which literally means "a stream of cold water".
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/kenya-nairobi-river-reels-under-weight-trash
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/all-africa
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-pollution
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/river-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/solid-waste
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/kenya
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/freshwater-ecosystems
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-supply
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/africa